ASA 125th Meeting Ottawa 1993 May

5aUW12. Matched-field estimation of scattering from Arctic ice---Analysis
of the CEAREX 89 field experiments.

Tarun K. Kapoor

Henrik Schmidt

Dept. of Ocean Eng., MIT, Cambridge, MA 02139

Scattering experiments were conducted in 1989 in the Norwegian--Iceland
Sea using explosive charges detonated at varying depths. The scattered field
was received at a crossed horizontal hydrophone array positioned at a depth of
60.0 m. In this paper, the scattering of low-frequency acoustic waves from the
Arctic Ice sheet will be evaluated via matched-field processing of short-range
returns. Using near-field beamforming (focusing), which assumes a point
scatterer, it was possible to isolate the scattering hot spots under the ice
sheet. Essential inputs to this processing include the source location and shot
times which were determined using an adaptive least-squares estimator in a
matched-field approach. [Work supported by ONR.]